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Did a search and couldnt find anyone really with a ny noted problems with the Power2max.

Ive had one since Aug 2011 with no problems..............until last week. Tempo sessions where becoming very very difficult and I was a bit down that 2012 was going to be a slog! So I decided to do the old back to back on the turbo.

Now I know we have to take into account tyre heating up and turbo etc, but in the past, afteraround 20mins the turbo (Tacx I-Magic) would be reading around the same watts to within 8w. I set up, warm up and now, the differenc eis around 80-90w. The Power2max is reading way lower than the turbo. It stacks up when I look over my Garmin dwnloads, speed and effort (HR) in the past compared to now, with these NEW power2max readings. Done the freewheel to self calibrate etc, forced a reset on the Garmin etc. Still reads around 80w lower.

Anyone had the same issue with the Power2max?

Have emailed them and have o say they are great with response and I have shipped it back for checking, I await their response..............Im doomed if they say its fine though, a bad few mths lay ahead!! Though I cant rgue with the past comaprisons of data. Convinced it has developed a problem.

Search the Wattage Google group, and the Bikeradar blog for extensive discussions on P2M. It seems to be a good system in many ways but some devices have had problems with temperature instability and drift. If you are particularly fastidious about your Tacx Flow calibration/coast down, tyre pressure etc. then that should tell you something, if you aren't very consistent then forget the flow. Are you building in extensive periods of coasting on the turbo to allow the P2M to zero?

Worth noting that turbo use, with no freewheeling, is a pretty stern test of any powermeter's stability. Can you use the P2M outside, perhaps with a known good Powertap out back, to test it a bit more?

petromyzon wrote:Search the Wattage Google group, and the Bikeradar blog for extensive discussions on P2M. It seems to be a good system in many ways but some devices have had problems with temperature instability and drift. If you are particularly fastidious about your Tacx Flow calibration/coast down, tyre pressure etc. then that should tell you something, if you aren't very consistent then forget the flow. Are you building in extensive periods of coasting on the turbo to allow the P2M to zero?

Worth noting that turbo use, with no freewheeling, is a pretty stern test of any powermeter's stability. Can you use the P2M outside, perhaps with a known good Powertap out back, to test it a bit more?

Very true, there are extensive discussions about its use, drift, freewheel to zero etc, but no one has actually said they have done a back to back with a result of around 80watts difference in any discussion.

I am pretty serious about the turbo, tyre pressure, ride till warmed up, reset the calibration coast down etc and have always had around 10watts difference max. Im convinced I have a problem, its on its way back to Germany for checking so will have to wait and see.

Just curious if anyone out there have had similar with their unit yet? Temperature does affect it, but this is a massive difference in watts, now making a tempo session become a threshold!

Just to sign off on this one, I received my replacement Power2max today, fitted and can now say Im back in the normal world again with power figures.

Setup on the same back to back as done before sending the unit away, Im now within 15w of the turbo (Im not sure I warmed the tyre up as much as the previous test, about 5mins less this time).

So, I emailed P2M on 1st Feb to notify the problem, they respond within 3hrs. I ship the unit to them on the 2nd Feb. They receive it on the Monday 6th. Test same day and ship a return unit to me on the 7th. Not a bad service at all! I asked them for a report on their findings (which I detailed in the earlier post) so all in all, a very good service. Gotta not gloss over the fact the unit went wrong in the first place, but credit where its due, P2M did solve it with a new unit no questions asked.